Reversing a vehicle while towing a trailer can be challenging for many drivers, particularly for drivers that drive with a trailer on an infrequent basis or with various types of trailers. Some systems used to assist an operator in backing a trailer rely on hitch angle measurements to determine the position of the trailer relative to the vehicle. Thus, the accuracy and reliability of the hitch angle measurements can be critical to the operation of the trailer backup assist system. In systems employing imager-based hitch angle detection, improper calibration of an imaging device can lead to inaccurate hitch angle measurements. Furthermore, in instances where the imaging device becomes obstructed, such systems may be forced offline and rendered unable to determine a hitch angle between the vehicle and the trailer. To function properly, some systems require a user to input measurements such as trailer length. This is not only cumbersome on the user but may lead to erroneous measurements being inputted to the system. Accordingly, there is a need for a trailer backup assist system that overcomes the problems mentioned above. The present disclosure is intended to satisfy this need.